As publicly known, a scroll compressor has been known such that a suction chamber is at an outer peripheral portion of the compressor, a discharge port is provided at a central portion of a swirl or scroll, and fluid is successively compressed through two symmetrical scroll compression spaces, which join each other at the discharge port, from the outer peripheral portion of the compressor toward a compression chamber defined at the center thereof. The structure of a conventional scroll compressor is illustrated in FIGS. 1 and 4. There are provided a scroll compressor 2 and a motor 3 in a sealed container 1. The scroll compressor 2 mainly comprises a stationary scroll 4, an orbital scroll 5, a self-rotation prevention mechanism 6, a crank shaft 7, a frame 8, and a bearing 9. The stationary scroll 4 has a scroll wrap 11 which stands upright on an end plate 10. As conventionally known, the wrap 11 is configured with a curved line which is made up of an involute curve and a circular arc combined, or the like shape. Also, the stationary scroll 4 is provided with a suction port 12 for sucking gas to be compressed at its outer periphery, a suction chamber 13 in communication with the suction port 12, and a discharge port 14 at a central portion thereof. On the other hand, the orbital scroll 5 has an end plate 15 and a scroll wrap 16 standing upright thereon. The configurations of the respective wraps 11 and 16 of the stationary scroll 4 and the orbital scroll 5 are in plane-symmetry relation and offset or deviated from each other by an angle of 180.degree.. Further, because the stationary scroll 4 and the orbital scroll 5 are meshingly engaged with each other with the centers of the scrolls deviated from each other by a length of a radius of an orbiting movement of the latter, the two wraps 11 and 16 are in contact with or in a condition of being closest to each other (represented as "contact", hereinafter) at a plurality of positions so that a plurality of compression chambers 17 are defined. The orbital scroll 5 has a boss portion 18 on its rear surface, into which the crank shaft 7 is inserted. The self-rotation prevention mechanism 6 is arranged between the rear surface of the orbital scroll 5 and the frame 8. The crank shaft 7 is supported by the frame 8 via the bearing 9. A rotor of the motor 3 is fixed to one end of the crank shaft 7 and the other end thereof is inserted into the boss portion 18 of the orbital scroll 5. With the above-described arrangement, when the crank shaft 7 rotates by the driving of the motor 3, the orbital scroll 5 makes an orbiting movement with respect to the stationary scroll 4, maintaining its posture as it is by the function of the self-rotation prevention mechanism. Then, the compression chambers 17 defined by the stationary scroll 4 and the orbital scroll 5 engaged with each other gradually move from the outer peripheral portions of the scrolls to the central portion thereof owing to the orbiting movement of the orbital scroll 5 so that the volume of each compression chamber is decreased. As a result, low-pressure gas sucked from the suction port 12 flows through the suction chamber 13, is compressed in the above process and is discharged from the discharge port 14 of the scroll compressor 2 into the sealed container 1. After that, the high-pressure gas in the sealed container 1 is delivered through a discharge pipe 19 to the outside of the compressor.
FIG. 1 shows a plane view of the both scroll wraps. Compression is started after the orbital scroll 5 which makes the orbiting movement has been in contact with terminal ends 11a and 11b of the stationary scroll wrap 11. A distance or gap between the both scroll wraps in a radial direction thereof is set at zero or a very small value in order to provide a good seal between them. In other words, the orbital scroll 5 orbits while colliding against the terminal end 11a of the stationary scroll wrap. This collision may bring about destruction of the both scroll wraps or may cause noises. The orbital scroll 5 makes its orbiting movement while also colliding against the terminal end 11b of the stationary scroll wrap. Because of the collision, breakage of the both scroll wraps may be caused or noises may be generated.